The bacterial SoxAX cytochromes

Kappler, Ulrike and Maher, Megan J. (2013) The bacterial SoxAX cytochromes. Cellular and Molecular Life Science, 70 6: 977-992. doi:10.1007/s00018-012-1098-y

Author Kappler, Ulrike
Maher, Megan J.
Title The bacterial SoxAX cytochromes
Journal name Cellular and Molecular Life Science   Check publisher's open access policy
ISSN 1420-682X
Publication date 2013-03
Year available 2012
Sub-type Article (original research)
DOI 10.1007/s00018-012-1098-y
Volume 70
Issue 6
Start page 977
End page 992
Total pages 16
Place of publication Basel, Switzerland
Publisher Birkhaeuser Verlag AG
Collection year 2013
Language eng
Formatted abstract
SoxAX cytochromes are heme-thiolate proteins that play a key role in bacterial thiosulfate oxidation, where they initiate the reaction cycle of a multi-enzyme complex by catalyzing the attachment of sulfur substrates such as thiosulfate to a conserved cysteine present in a carrier protein. SoxAX proteins have a wide phylogenetic distribution and form a family with at least three distinct types of SoxAX protein. The types of SoxAX cytochromes differ in terms of the number of heme groups present in the proteins (there are diheme and triheme versions) as well as in their subunit structure. While two of the SoxAX protein types are heterodimers, the third group contains an additional subunit, SoxK, that stabilizes the complex of the SoxA and SoxX proteins. Crystal structures are available for representatives of the two heterodimeric SoxAX protein types and both of these have shown that the cysteine ligand to the SoxA active site heme carries a modification to a cysteine persulfide that implicates this ligand in catalysis. EPR studies of SoxAX proteins have also revealed a high complexity of heme dependent signals associated with this active site heme; however, the exact mechanism of catalysis is still unclear at present, as is the exact number and types of redox centres involved in the reaction.
Keyword Crystal structure
Heme thiolate proteins
Redox centres
SoxAX cytochromes
Sulfur Oxidation
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online: 21 August 2012.

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Chemistry and Molecular Biosciences
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Created: Fri, 28 Sep 2012, 15:35:49 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences